Area Forecast Discussion
Issued by NWS Blacksburg, VA
Issued by NWS Blacksburg, VA
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781 FXUS61 KRNK 140755 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 355 AM EDT Sun Jul 14 2024 .SYNOPSIS... Well above normal to near record warm temperatures will be found across the region through Tuesday. Only an isolated shower or storm is expected this afternoon, with scattered storms possible Monday and Tuesday as moisture builds across the region. The best chance for showers and storms will be on Wednesday and Thursday as a cold front dips south through our area. && .NEAR TERM /THROUGH TONIGHT/... As of 215 AM EDT Sunday... 1. High confidence for well above normal temperatures through the period with near record high minimum temperatures possible Monday morning at Roanoke. Confidence is high that well above normal temperatures will prevail through the near term period, as anomalously high 850mb temperatures, one to three standard deviations above normal today and two to three plus standard deviations above normal Monday are expected. The NBM guidance was the warmest of all the guidance reviewed and was used for the temperature forecast. This guidance produces a 100 degree high at Roanoke for Monday which seems quite plausible considering ROA reached 98 on Saturday. If this verifies, it would be the first 100 degree day at ROA since July 20, 2020. The spread in the individual NBM members for both high and low temperatures today and Monday where generally within 2 to 3 degrees yielding high confidence in the temperature forecast. The only potential factor that could keep temperatures below forecast values would be if showers or storms, or debris cloud cover from complexes of storms to our west impacted the area. Chances for showers and storms today appear extremely limited as the HREF shows the highest probability of CAPES exceeding 1000 j/kg east of our area and east of a weak surface boundary. Terrain induced isolated storms along the southern Blue Ridge are also possible, but a large majority of the area will remain dry. Complexes of storms across the southern Great Lakes and Upper Missouri Valley this morning should remain to our west and/or weaken as they move southeast. A slightly better chance for showers and storms is expected Monday with increasing PWAT values, higher CAPES, and faint upper level disturbances crossing an slightly more progressive flow. A continued deep west flow should limited precip coverage and feel the 00Z HRW FV3 forecast of scattered to pockets of likely POPs Monday afternoon are overdone. Kept POPs at a slight chance for most areas Monday. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 300 AM EDT Sunday... Key Messages: 1. Above normal temperatures and heat indices above 100 degrees possible Monday and Tuesday. 2. Isolated to scattered afternoon showers and storms. Mostly zonal flow aloft and surface high pressure over the area start off the work week. Subsidence from the high will keep temperatures on a warming trend, increasing to above seasonal normals for Monday and Tuesday. Probabilities of temperatures in the Piedmont and Southside, and Roanoke Valley, reaching 95 degrees or greater is around 90% for the first half of the week. Temperatures may reach record values on Monday and Tuesday, please reference the Climate section of the forecast discussion for current record highs and record high minimum temperatures. Heat indices will also be high, near 100 to 105 degrees, east of the Blue Ridge, so Heat Advisories may be needed. Plenty of daytime heating and modest moisture, and a weak upper shortwave passing north of the area, could lead to isolated to scattered showers and storms developing along the higher terrain each afternoon. However, with a lack of strong forcing and substantial moisture, severe potential is limited, and any activity should wane after sundown. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 300 AM EDT Sunday... Key Messages: 1. Increasing chances and coverage of showers and storms by midweek. 2. Continued above normal temperatures and high heat indices through Wednesday. 3. Slightly cooler temperatures to end the work week. By midweek, troughing will deepen into the upper Midwest and Great Lakes region, while a surface low pushes northeastward into eastern Canada, with a trailing cold front moving into the northeast and Mid Atlantic. This system will bring increased chances and coverage of showers and thunderstorms to the area along and ahead of the front, as early as Wednesday afternoon. The front looks to move slowly towards the southeast, not reaching the coast until the end of the work week. With the front over the area, shower and storms chances continue through at least Thursday or Friday morning, until the front exits the area. Southwesterly flow at the surface and aloft will advect greater moisture into the area from the Gulf, with precipitable water values increasing to the 90th percentile relative to climatology, in the 1.5 to 2 inch range, by Wednesday afternoon. With plenty of ambient moisture, and showers/storms have the potential to produce moderate to heavy rainfall. Strong heating and ample moisture, along with the better forcing and shear from the front, storms may be more widespread Wednesday and Thursday, though it is still too far out to discern mesoscale details, and thus severe potential, at this time. Following the front, a drier and cooler airmass works its way into the region to start the weekend, bringing temperatures down, closer to seasonal norms, in the upper 70s to low 80s, for Friday and Saturday. Cloud cover and rain may also keep temperatures cooler on Thursday, but Wednesday may still be well above normal, depending on the timing of precipitation. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... As of 115 AM EDT Sunday... Early Sunday morning VFR conditions were noted across the region and confidence is high that VFR conditions will persist through the TAF period, with the exception of IFR to LIFR fog at KLWB early Sunday morning from 10-13Z. Isolated showers and storms Sunday afternoon will primarily be focused along the southern Blue Ridge and the probability of this isolated activity impacting any TAF sites today are extremely low. West to southwest winds less than 10 knots are expected through 06Z Monday. AVIATION OUTLOOK... Daily afternoon SHRA/TSRA chances continue each day through Tuesday, and dissipate at night. A front crosses the region Wednesday and Thursday, bringing more widespread SHRA/TSRA and sub-VFR conditions. && .CLIMATE... As of 715 PM EDT Saturday... Blacksburg tied the record high for today of 92 degrees. The previous record was set in 1936. Roanoke managed 98 degrees, one shy of the record of 99 set in 1954. Except for perhaps the daytime high for Blacksburg on July 16, we currently are not forecasting record high temperatures or record maximum low temperatures Monday, July 15, and Tuesday, July 16, values will be close enough that some folks might be curious what the records are. Below you will find a table that lists these values for different locations in our region and the years those records were set. ************* RECORDS FOR July 15 ************* +=============================================+ | LOCATION | RECORD HIGH | RECORD MAX LOW | | Blacksburg | 99 in 1954 | 72 in 1954 | | Bluefield | 91 in 1951 | 72 in 1942 | | Danville | 104 in 1936 | 79 in 1922 | | Lynchburg | 101 in 1936 | 77 in 1988 | | Roanoke | 103 in 1936 | 74 in 1995 | +=============================================+ ************* RECORDS FOR July 16 ************* +=============================================+ | LOCATION | RECORD HIGH | RECORD MAX LOW | | Blacksburg | 93 in 1983 | 70 in 2020 | | Bluefield | 96 in 1988 | 71 in 1980 | | Danville | 102 in 1934 | 77 in 1920 | | Lynchburg | 103 in 1934 | 76 in 1937 | | Roanoke | 100 in 1988 | 74 in 2020 | +=============================================+ && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PH NEAR TERM...PH SHORT TERM...AS LONG TERM...AS AVIATION...PH CLIMATE...DS